Book III about halite and nitrium, alum and acrid juices and related minerals, sulphur, bitumen, realgar, and orpiment; the fourth, chrysocolla, aerugo, caeruleum, ferrugo Page 53



	BOOK III	41

	tected from putrefaction. The flesh of fish and other animals that we eat can be preserved unimpaired when sprinkled with this mineral. It is not only used on meat but also on cheese, butter and some fruit such as the caper. Some olives, lemons and other fruits can be preserved for a long time by placing them in brine. The drier, harder less friable and more astringent a salt the more useful it becomes for salting and curing. Halite or rock salt is the best. Among marine salts, that from Megara is considered the best and among artificial salts, that made from Stassfurt brine. The driest salts are the most salty; the hardest dissolve the slowest; the most astringent unite the essence of the salted substance most strongly. When used in medicine salt dries the body and even when mixed with other substances it retains its drying power. It cleanses and is astringent ; the more astringent or bitter it is, the less it cleanses. All salt is only slightly astringent when compared with astringent minerals such as alums, sulphates and related minerals. However various salts differ greatly in this property. Halite is more astringent than any marine, lacustrine, or artificial salt. Certain natural, lacustrine, and artificial salts are more cleansing than astringent although the tongue can detect a certain bitter taste in all of them. This distinguishes these salts from the other two genera. Natural sal ammoniac occurs with halite in the lacustrine salt from the Dead Sea and artificial sal ammoniac (sal ammoniacus subdit-icus) forms with certain manufactured salts. Sometimes, in one and the same ore, salts of both the first and third³ genera are found together. Dioscorides recommends halite as a remedy and even sal ammoniac. Pliny recommends that Tattaeum or Caunos salt be added to salves and plasters. The Spaniards use it for eyes that have been blackened and discolored by blood, the result of a blow. It is used by the Thebans for itch, leprosy and mange. Its healing properties are known from experience and one learns through conversations the diseases it will cure so further discussion is unecessary. A dram of salt in a glass of wine sooths the stomach. The black Sarmatian salt found in cross-cutting veins is used today for this purpose. Salt was prepared and sold fraudulently in former times and the practice has continued to the present day. Cubes and porous pieces of marine salt are selected and substituted for the white Indian salt that occurs in octahedrons as I have stated above. Sal ammoniac is not only adulterated with Cocanician and Cyprian salt, as mentioned by Pliny, but also with the artificial salt. Each adulteration is easily detected. Marine salt crackles and decrepitates in fire while the Indian mineral does not. Artificial sal ammoniac forms in lozenges⁴ and neither crackles nor decrepitates in a fire but is entirely consumed.⁶ Native sal ammoniac occurs ³ Sulphur, bitumen, realgar, etc. ⁴ Although native sal ammoniac crystallizes in the isometric system, artificial crystals have been observed with rhombohedral symmetry. ⁶ Sal ammoniac, NH₄C1, sublimes without fusion under certain conditions.